Using cDNA preparations to partially purified alpha-globin mRNA to prepare pure beta-globin mRNA and cDNA will allow purification of alpha-globin mRNA and hence pure alpha- and beta-globin cDNA on immobilized supports. These preparations will be used to measure the absolute rates of alpha- and beta-globin mRNA synthesis in 3H adenosine labelled RNA from early and late rabbit erythroblasts using the Firefly luciferase assay to measure ATP pool specific activity. In addition, non-globin mRNA synthesis in early and late erythroblasts will be measured. By use of 3H nucleoside labelled mRNA preparations, ribosome binding site sequences for alpha- and beta-globin mRNA will be determined. A model of RNA synthesis in the nucleus using large molecules as precursors of mRNA which uses both exonucleolytic and endonucleolytic degradation will be fitted to data obtained for RNA extracted from short term labelled nuclei and assayed as total RNA and poly(A) containing RNA will be further developed using known synthesis and degradation rates. BIBLIOGRAPHIC REFERENCE: The nature of the 5'-linked 5' nucleotide sequence at the 5' end of rabbit globin messenger RNA. John A. Hunt and Gary N. Oakes. Biochem. J. 155:637-644 (1976).